Pentest Notes: PowerShell Automation - Basics
These notes cover PowerShell automation for penetration testing, focusing on practical applications and techniques.
What is PowerShell?
A powerful scripting language and command-line shell built on the .NET framework, heavily integrated with Windows. Ideal for system administration and automation, making it a valuable tool for pentesters.
Why PowerShell for Pentesting?
- Native to Windows: Pre-installed on most Windows systems.
- Object-oriented: Allows for complex data manipulation and interaction with APIs.
- Access to .NET Framework: Enables interaction with a vast library of classes and functions.
- Remoting capabilities: Execute commands on remote systems.
- Bypass security restrictions: Can be used to circumvent some security measures if not properly configured.
Basic Syntax
- Cmdlets: Commands in PowerShell (e.g., Get-Process,Get-Service,Get-ChildItem).
- Pipes (|): Used to chain cmdlets, passing the output of one cmdlet as input to the next.
- Objects: PowerShell works with objects, not just text.
- Variables: Use $to define variables (e.g.,$process = Get-Process).
Key Cmdlets for Pentesting
- System Information Gathering:
        - Get-WmiObject: Access WMI (Windows Management Instrumentation) for detailed system information (e.g., OS version, hardware details, installed software).
- Get-ComputerInfo: Provides a summary of computer information.
- Get-Process: Lists running processes.
- Get-Service: Lists services.
- Get-LocalUser: Lists local users.
- Get-NetIPAddress,- Get-NetAdapter: Network information.
 
- File System Interaction:
        - Get-ChildItem: Lists files and directories (equivalent to- diror- ls).
- New-Item: Creates files and directories.
- Remove-Item: Deletes files and directories.
- Get-Content: Reads file content.
- Set-Content: Writes content to a file.
 
- Networking:
        - Test-NetConnection: Checks network connectivity and port status (equivalent to- pingor- telnet).
- Invoke-WebRequest: Sends HTTP requests (useful for web application testing).
 
- Security:
        - Get-EventLog: Retrieves event logs (useful for post-exploitation and log analysis).
- Get-Acl: Retrieves Access Control Lists (ACLs) for files, directories, and other objects.
 
- Execution:
        - Invoke-Expression: Executes a string as a PowerShell command (use with caution due to security risks).
- Start-Process: Starts a new process.
 
- PowerShell Remoting:
        - Enabling Remoting: Enable-PSRemoting.
- Connecting to Remote Systems: Enter-PSSession -ComputerName "hostname/IP".
- Executing Commands Remotely: Invoke-Command -ComputerName "hostname/IP" -ScriptBlock { "Commands" }.
- CredSSP: Delegate credentials for multi-hop scenarios.
 
- Enabling Remoting: 
Exploitation Techniques
- Bypassing Execution Policies:
        - Set-ExecutionPolicy Bypass -Scope Process: Bypasses execution policy for the current process.
- Encoding/Obfuscation: Techniques to evade detection by security software.
 
- Credential Dumping:
        - Mimikatz: A powerful tool for extracting credentials from memory (often used with PowerShell).
- PowerShell scripts for extracting credentials from LSASS.
 
- Lateral Movement:
        - Using PowerShell Remoting and credential theft to move between systems within a network.
- Web Shells: Deploying web shells using PowerShell for persistent access.
 
Defense Evasion
- Obfuscation: Encoding, string manipulation, and other techniques to make PowerShell scripts harder to analyze.
- AMS (Antimalware Scan Interface) Bypass: Techniques to avoid detection by AMS.
- Logging and Monitoring Evasion: Techniques to minimize logging and avoid detection by security monitoring tools.
Resources and Tools
- PowerSploit: A collection of PowerShell modules for penetration testing.
- Nishang: Another collection of PowerShell scripts and modules for offensive security.
- Invoke-Obfuscation: A PowerShell obfuscation framework.
- Empire: A post-exploitation framework that uses PowerShell agents.
- PSAttack: PowerShell Attack Framework.
Best Practices
- Code Review: Always review PowerShell scripts before executing them.
- Principle of Least Privilege: Use the minimum necessary privileges when executing PowerShell commands.
- Logging and Monitoring: Implement proper logging and monitoring to detect malicious PowerShell activity.
- Constrained Language Mode: Restricts PowerShell to a subset of its functionality, limiting the impact of malicious scripts.
- Application Control: Whitelisting allowed PowerShell scripts and modules.
Example Snippets
- Get System Info:
        Get-WmiObject Win32_OperatingSystem | Select-Object Caption, Version, BuildNumber
- Check Port:
        Test-NetConnection -ComputerName <IP/Hostname> -Port <Port>
- Download File:
        Invoke-WebRequest -Uri <URL> -OutFile <LocalPath>
IX. Conclusion
PowerShell is a powerful tool for penetration testing. Understanding its capabilities and limitations is essential for both offensive and defensive security. These notes provide a starting point for learning PowerShell automation for pentesting. Continuous learning and practice are key to mastering this valuable skill.
This outline provides a more structured and comprehensive set of notes. Remember to practice these techniques in a safe and legal environment.
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